Harry E. Walker/MCTWashington Wizards Gilbert Arenas (0) is guarded by New Jersey Nets Rafer Alston (1) during their game played at the Verizon Center in Washington, D.C. on Saturday.CHARLOTTE — Their best player is out for at least a week, their chemistry is like a science project gone terribly wrong, and the team looks as though it’s coming apart before it has a chance to come together.

So naturally, the Nets, off to an 0-3 start, are relying on one guy to pull this team of kids together — a 33-year-old point guard who has 18,001 minutes on his NBA odometer.

No problem, Rafer Alston says — just repeat after me: Get the defense fixed, and we’ll take it from there.

“We’re not there,” the veteran said in the aftermath of Saturday’s slaughter at Washington. “That’s been there since training camp — think defense first. We can figure out offense — we scored over 100 tonight. But they shot 60-something percent, that just tells you we’re not there.

“When we get to the next practice and meeting, our mind-set better be defense and defense only, and don’t even think about offense at this point. Because right now they’re carving us up every night defensively.”

The Nets yielded 123 points on 61.5 percent shooting at D.C., and when it ended every last man was checking for powder burns. They were not only inattentive to their game plan, they were indifferent, soft, and — as Brook Lopez put it, “afraid — some guys are afraid that the help won’t be there.”

Basically, they played defense like strangers thrown together that afternoon.

“Defensively we’ve got to keep growing as a unit and get comfortable with each other and different rotations and matchups out there,” said Courtney Lee, who had a rough time guarding Gilbert Arenas, with little help.

“We played with one unit in practice, you get comfortable with that and then you never know, injuries may occur. We just got to get comfortable in knowing each other’s games and help each other out, basically. We have to have somebody in the background ready to step up and help them.”

They might want to get their act together quickly, because tonight’s game at Charlotte looks like the only potential ‘W’ on the schedule for the next two weeks. And they may have to get through the next fortnight without Devin Harris, who is out for at least four more games with a groin strain.

The only positive to this revolting development was that Alston was their best player in Washington, where he had 20 points and eight assists in 31 minutes.

He vows that the additional workload won’t be a problem.

“I’m in great condition,” Alston said. “That’s one thing, even though I’m getting up there in age: I pride myself every summer at staying in great shape. Guys like (Sam) Cassell told me a long time ago, stay ready. One way you have to be ready is to just stay in condition. So if need be, I can go the distance.”

Getting tough: Lawrence Frank had this take on the Douglas-Roberts’ suggestion that the players must “protect each other” and “send messages” when one of their own incurs a hard foul:

“Generally speaking, for us, it’s incumbent to always have each other’s back,” the coach said. “We want to have a hit-first mentality, we want to be proactive. You always have to have your teammate’s back. Regardless of anything that happens, that’s part of being a team and being together.”

Frank actually presaged CDR’s remarks in the postgame Saturday, when he expressed his disgust at the lack of “paint consequence.”

Hassell out: If this seems like a good time to plug Trenton Hassell into the rotation — just to match up with Gerald Wallace or Boris Diaw — it’s not going to happen: The veteran defensive specialist left the team Sunday to attend to a personal matter. He’s planning to rejoin them at practice tomorrow.

Bad omen: The Nets are 0-3, which is never a good harbinger: The last time they started off the season 0-3 was in 1999-00 — Don Casey’s only full year — when they finished with a 31-51 record.